Meeting Abstract
Annual hypoxia in the Chesapeake Bay has expanded to the point that juvenile striped bass routinely encounter it and thus their Darwinian fitness may depend upon their ability to perform there. Because locomotion that is critical to predator/prey dynamics relies primarily on white muscle, it was thought to be largely unaffected by hypoxia. However, minimal work has been done to investigate anaerobically powered performances under hypoxia. We subjected juvenile striped bass to three performance tests, sprint swimming, escape response, and prey capture, under acute hypoxia (20% AS) and normoxia (>80% AS). We found a significant, repeatable reduction in sprint swimming performance of juvenile striped bass during hypoxia exposure. Preliminary results also show that responsiveness is lower in hypoxia compared to normoxia, while the locomotor parameters of the escape response are only mildly affected. Furthermore, preliminary results suggest that hypoxia influences prey capture dynamics in a manner that varies strongly by individual. Specific kinematics affected by hypoxia will also be reported. Since the energy to fuel these types of locomotion comes from existing ATP and creatine phosphate stores, the altered performance probably reflects malfunction somewhere along the reflex chain leading from detection of external stimuli to the muscle contraction itself. In addition, defects in vision under hypoxia may be involved.
